Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
75 Cards in this Set
- Front
- Back
|
the adrenal medulla releases which hormones |
epinephrine & norepinephrine |
|
|
the adrenal cortex releases which hormone |
corticosteroids |
|
|
what is the effect of epinephrine and norepinephrine on heart rate, blood vessels, etc.? |
increases heart rate
vasoconstriction
converts glycogen into glucose for transport in blood |
|
|
the _____ is the master switch for the pituitary gland & regulates the pituitary gland |
hypothalamus |
|
|
what is bifurcation? |
the splitting of blood vessels into smaller vessels |
|
|
what does hydrocortisone (cortisol) do? |
it regulates the conversion of fats, proteins, & carbohydrates to energy for muscles
it enhances blood pressure, inhibits basophils |
|
|
what does histamine do? |
increases capillary permeability so WBCs can leave blood vessel into infected tissues |
|
|
what does corticosterone do? |
works with cortisol to regulate immune response to stress |
|
|
What hormone does the hypothalamus release? |
Corticotrophin-releasing hormone [goes to pituitary gland] |
|
|
What hormone does the anterior pituitary gland release? |
Adrenal coticotrophic hormone [into blood, goes to adrenal glands] |
|
|
Corticosteroid hormones= |
Glucocorticoids + mineralcorticoids |
|
|
Stress leads to production of epinephrine which leads to.... |
Platelet production & aggregation |
|
|
What are coronary arteries? |
Arteries from aorta to heart |
|
|
What is myocardial ischemia? |
Coronary arteries become clogged and the supply of oxygen and glucose to the myocardium are limited.
Symptom: angina pectoris |
|
|
Prolonged stress leads to long term high blood pressure which leads to... |
Left ventricular hypertrophy, irregular heartbeat, and then sudden cardiac arrest
|
|
|
What is smooth muscle? |
It is muscle located in the wall of internal structures, such as blood vessels, stomach & intestines; not striated, often regulated by neurotransmitters & hormones; mostly involuntary |
|
|
Why the left ventricle? |
Because it has the most work to do! Blood leaves the LV and is pumped throughout the body (systemic circulation) |
|
|
What is an axon?
|
A single, long process of a nerve cell that propagates a nerve impulse toward axon terminals |
|
|
What is repolarization?
|
Membrane potential of a cell becomes negative again, returning to resting membrane potential, usually by an efflux of cations leaving the cell |
|
|
What is hyperpolarization?
|
Membrane potential of a cell becomes more negative than resting membrane potential, often caused by an efflux of cations or an influx of anions |
|
|
What is a motor unit?
|
Motor neuron + all skeletal muscle cells that the neuron stimulates |
|
|
What is an axon terminal?
|
Where synaptic vesicles perform exocytosis and release neurotransmitter molecules |
|
|
What is the sarcolemma?
|
The cell membrane of a skeletal or cardiac muscle fiber (cell), along which AP is propagated |
|
|
What is the sarcoplasm?
|
The cytoplasm of a muscle cell that contains myofibrils |
|
|
What is a synapse? |
Junction between 2 neurons or a neuron and a muscle or gland; communication between cells; electrical or chemical (i.e. Neurotransmitters) |
|
|
What is a synaptic cleft?
|
A gap that separates 2 cells at a synapse |
|
|
Why is the Resting Membrane Potential negative?
|
1. There are more proteins on the inside of the cell than the outside of the cell (tend to be negatively charged) |
|
|
What is a graded potential?
|
A small deviation from resting membrane potential that increases or decreases polarization
|
|
|
What is depolarization?
|
Membrane potential of a cell becomes less negative, usually by an influx of cations into the cell, resulting in an action potential |
|
|
what is action potential? |
an electrochemical signal that spreads along the membrane of a muscle fiber to stimulate contraction; briefly reverses the membrane potential and then restores it to the resting state (carried by a motor neuron) |
|
|
what is a motor neuron? |
neurons in the brain or spinal cord that extend axons to stimulate muscle contraction via action potential |
|
|
what is a neuromuscular junction (NMJ) |
a synapse between an axon terminal of a motor neuron and sarcolemma of a skeletal muscle cell; AP is an electrical signal in axon, becomes chemical across synapse, then electric again in muscle [region where motor neuron & skeletal muscle interaction] |
|
|
why is the resting membrane potential maintained? |
1. intracellular anions are bound in the cytoplasm
2. there are more proteins on the inside of the cell than the outside (proteins tend to be negatively charged)
3. sodium-potassium pump: keeps negative charge inside of cell |
|
|
the sodium-potassium pump pumps out 3 _____ for every 2 ____ it brings back in |
sodium, potassium |
|
|
the sodium potassium pump goes _____________ |
against the concentration gradient (against diffusion!) |
|
|
what is graded potential? |
a small deviation from resting membrane potential that increases or decreases polarization
it varies in amplitude, can summate (possibly to AP if past the threshold) or can cancel each other out (if opposite charges) |
|
|
what is the magic number for AP and depolarizaion? |
the threshold is -55 mV! |
|
|
what are myofibrils? |
threadlike structure of a muscle cell consisting of thick filaments and thin filaments (proteins) |
|
|
what are the thick filaments? |
myosin |
|
|
what are the thin filaments? |
actin, troponin, tropomyosin |
|
|
what is a sarcomere? |
a contractile unit of a striated muscle cell extending from one Z disc to the next (what physically contracts) |
|
|
what is a synaptic vesicle? |
membrane-bound sac that stores neurotransmitters for release into the synaptic clet |
|
|
what is acetylcholine (Ach)? |
an excitatory neurotransmitter at NMJ that transfers AP from neuron to muscle cell |
|
|
what is Acetylcholinesterase (AchE)? |
an enzyme in synaptic cleft to stop synaptic transmission of acetylcholine by breaking it up into choline + acetic acid |
|
|
what is a transverse (T) tubule? |
infolding of sarcolemma to allow membrane depolarization, and AP, to quickly reach the interior of the cell |
|
|
what is the sarcoplasmic reticulum |
smooth endoplasmic reticulum of muscle cells that store calcium during muscle relaxation and release calcium ions when muscle is stimulated by an action potential |
|
|
what is an A band? |
region within sarcomere, relatively dark, that has both thick filaments and portions of thin filaments; dark area |
|
|
what is an I band? |
less dense area of only thin filaments; light area |
|
|
in a relaxed muscle: |
tropomyosin (attached to troponin) covers the myosin-binding sites of actin & prevents their attachment to myosin
the release of calcium ions from the sarcoplasmic reticulum into the sarcoplasm initiates muscle contraction, dislodging troponin-tropomyosin complex from actin |
|
|
what is tetanus? |
condition by infection of Clostridium tetani with prolonged contraction of skeletal muscle fibers resulting in muscle tears.
the toxin blocks release of inhibitory neurotransmitters across the synaptic cleft by inactivation of a synaptic vesicle protein
similar for botulism, shellfish, and some spider or snake bite toxins |
|
|
what are symptoms and treatments of muscular dystrophy? |
symptoms: defect in muscle proteins, death of muscle cells and tissue, and progressive skeletal muscle weakness
treatments: limited to speech, respiratory, and physical therapy, orthopedic devices and surgeries, coticosteroids to slow muscle degeneration |
|
|
in muscular dystrophy: absence of what leads to what |
the protein dystrophin:
1. links actin of muscular cell to support proteins of sarcolemma, which is linked do endomysium, a fibrous sheath outside the sarcolemma
2. regulates concentration of calcium ions in muscle cell (sarcoplasm) |
|
|
what is a lever? |
a rod (BONES) that moves about a fixed point, the fulcrum (JOINTS) |
|
|
what is resistance? |
a force (LOAD) that opposes movement; the weight of a body part that is to be moved |
|
|
what is effort? |
a force exerted to achieve an action |
|
|
what is an example of a first class lever? |
seesaw; head resting on vertebral column
the fulcrum is between the effort and the resistance |
|
|
what is an example of a second class lever? |
wheelbarrow; body on toes
the fulcrum is at one end with the effort on the opposite side |
|
|
what is an example of a third class lever? |
flexing of the forearm at the elbow -- most common levers of the body
consist of a fulcrum at one end, load at opposite end, and effort between them |
|
|
what is an intercalated disc? |
fiber ends connected by thick sarcolemma |
|
|
what are desmosomes? |
they clam the fibers together |
|
|
what are gap junctions? |
they allow the AP to spread from one fiber to the next |
|
|
what are autorhythmic fibers? |
self-excitable cells that repeatedly generate AP that trigger heart contractions; it has 2 functions, the pacemaker and the cardiac conduction system
the initiation of contraction doesn't come from the brain or spinal cord! |
|
|
what is the pacemaker? |
it sets the rhythm of electrical activity that leads to heart contraction-- the SA node |
|
|
what is the cardiac conduction system? |
it ensures that cardiac chambers contract in a coordinated manner so that the heart provides an efficient pump; so the beat is regular and it beats exactly the same way every time |
|
|
why the SA node? |
the cells of the SA node become depolarized much faster than other cells of the heart, it's 100x faster than the other autorhythmic cells |
|
|
what is the final goal of the cardiac conduction system? |
ventricles contract, pump blood toward the semilunar (aortic and pulmonary) valves
electrochemical impulses from ANS modify timing and strength of heartbeats, but DO NOT ESTABLISH FUNDAMENTAL RHYTHM! |
|
|
what does an EKG do? |
it records cardiac action potential |
|
|
what is the P wave? |
atrial depolarzation as AP spreads form SA node to fibers in both atria, leading to their contraction |
|
|
what is the QRS complex? |
ventricular depolarization and contraction |
|
|
what is the T wave? |
ventricular repolarization as ventricles relax |
|
|
what could a flattened T wave mean? |
insufficient oxygen, possibly coronary heart disease |
|
|
what could an enlarged P wave mean? |
atrial enlargement, as with hypertension |
|
|
what could an enlarged Q wave mean? |
myocardial infarction (heart attack) |
|
|
what could an enlarged R wave mean? |
enlarged ventricles, as with hypertension |
|
|
what happens with the SA node and AP? |
AP propagates along atrial muscle cells to AV node
AP enters AV bundle (bundle of His), so AP travels from atria to ventricles |
